linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jing Liu <jing2.liu@linux.intel.com>
To: pbonzini@redhat.com, seanjc@google.com, kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, jing2.liu@intel.com
Subject: [PATCH RFC 4/7] kvm: x86: Add new ioctls for XSAVE extension
Date: Sun,  7 Feb 2021 10:42:53 -0500	[thread overview]
Message-ID: <20210207154256.52850-5-jing2.liu@linux.intel.com> (raw)
In-Reply-To: <20210207154256.52850-1-jing2.liu@linux.intel.com>

The static xstate buffer kvm_xsave contains the extended register
states, but it is not enough for dynamic features with large state.

Introduce a new capability called KVM_CAP_X86_XSAVE_EXTENSION to
detect if hardware has XSAVE extension (XFD). Meanwhile, add two
new ioctl interfaces to get/set the whole xstate using struct
kvm_xsave_extension buffer containing both static and dynamic
xfeatures. Reuse fill_xsave and load_xsave for both cases.

Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>
---
 arch/x86/include/uapi/asm/kvm.h |  5 +++
 arch/x86/kvm/x86.c              | 70 +++++++++++++++++++++++++--------
 include/uapi/linux/kvm.h        |  8 ++++
 3 files changed, 66 insertions(+), 17 deletions(-)

diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 89e5f3d1bba8..bf785e89a728 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -362,6 +362,11 @@ struct kvm_xsave {
 	__u32 region[1024];
 };
 
+/* for KVM_CAP_XSAVE_EXTENSION */
+struct kvm_xsave_extension {
+	__u32 region[3072];
+};
+
 #define KVM_MAX_XCRS	16
 
 struct kvm_xcr {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 15908bc65d1c..bfbde877221e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3786,6 +3786,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_XCRS:
 		r = boot_cpu_has(X86_FEATURE_XSAVE);
 		break;
+	case KVM_CAP_X86_XSAVE_EXTENSION:
+		r = boot_cpu_has(X86_FEATURE_XSAVE) &&
+			boot_cpu_has(X86_FEATURE_XFD);
+		break;
 	case KVM_CAP_TSC_CONTROL:
 		r = kvm_has_tsc_control;
 		break;
@@ -4395,7 +4399,7 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,
 
 #define XSTATE_COMPACTION_ENABLED (1ULL << 63)
 
-static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu)
+static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu, bool has_extension)
 {
 	struct xregs_state *xsave;
 	struct fpu *guest_fpu;
@@ -4403,9 +4407,14 @@ static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu)
 	u64 valid;
 
 	guest_fpu = vcpu->arch.guest_fpu;
-	xsave = &guest_fpu->state.xsave;
+	xsave = __xsave(guest_fpu);
 	xstate_bv = xsave->header.xfeatures;
 
+	if (!has_extension) {
+		/* truncate with only non-dynamic features */
+		xstate_bv = xstate_bv & ~xfeatures_mask_user_dynamic;
+	}
+
 	/*
 	 * Copy legacy XSAVE area, to avoid complications with CPUID
 	 * leaves 0 and 1 in the loop below.
@@ -4450,7 +4459,7 @@ static void load_xsave(struct kvm_vcpu *vcpu, u8 *src)
 	u64 valid;
 
 	guest_fpu = vcpu->arch.guest_fpu;
-	xsave = &guest_fpu->state.xsave;
+	xsave = __xsave(guest_fpu);
 
 	/*
 	 * Copy legacy XSAVE area, to avoid complications with CPUID
@@ -4488,29 +4497,31 @@ static void load_xsave(struct kvm_vcpu *vcpu, u8 *src)
 	}
 }
 
-static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu,
-					 struct kvm_xsave *guest_xsave)
+static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu, u32 *region, bool has_extension)
 {
 	if (boot_cpu_has(X86_FEATURE_XSAVE)) {
-		memset(guest_xsave, 0, sizeof(struct kvm_xsave));
-		fill_xsave((u8 *) guest_xsave->region, vcpu);
+		if (has_extension)
+			memset(region, 0, sizeof(struct kvm_xsave_extension));
+		else
+			memset(region, 0, sizeof(struct kvm_xsave));
+
+		fill_xsave((u8 *)region, vcpu, has_extension);
 	} else {
-		memcpy(guest_xsave->region,
+		memcpy(region,
 			&vcpu->arch.guest_fpu->state.fxsave,
 			sizeof(struct fxregs_state));
-		*(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)] =
+		*(u64 *)&region[XSAVE_HDR_OFFSET / sizeof(u32)] =
 			XFEATURE_MASK_FPSSE;
 	}
 }
 
 #define XSAVE_MXCSR_OFFSET 24
 
-static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu,
-					struct kvm_xsave *guest_xsave)
+static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu, u32 *region)
 {
 	u64 xstate_bv =
-		*(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)];
-	u32 mxcsr = *(u32 *)&guest_xsave->region[XSAVE_MXCSR_OFFSET / sizeof(u32)];
+		*(u64 *)&region[XSAVE_HDR_OFFSET / sizeof(u32)];
+	u32 mxcsr = *(u32 *)&region[XSAVE_MXCSR_OFFSET / sizeof(u32)];
 
 	if (boot_cpu_has(X86_FEATURE_XSAVE)) {
 		/*
@@ -4520,13 +4531,13 @@ static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu,
 		 */
 		if (xstate_bv & ~supported_xcr0 || mxcsr & ~mxcsr_feature_mask)
 			return -EINVAL;
-		load_xsave(vcpu, (u8 *)guest_xsave->region);
+		load_xsave(vcpu, (u8 *)region);
 	} else {
 		if (xstate_bv & ~XFEATURE_MASK_FPSSE ||
 			mxcsr & ~mxcsr_feature_mask)
 			return -EINVAL;
 		memcpy(&vcpu->arch.guest_fpu->state.fxsave,
-			guest_xsave->region, sizeof(struct fxregs_state));
+			region, sizeof(struct fxregs_state));
 	}
 	return 0;
 }
@@ -4642,6 +4653,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	union {
 		struct kvm_lapic_state *lapic;
 		struct kvm_xsave *xsave;
+		struct kvm_xsave_extension *xsave_ext;
 		struct kvm_xcrs *xcrs;
 		void *buffer;
 	} u;
@@ -4847,7 +4859,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		if (!u.xsave)
 			break;
 
-		kvm_vcpu_ioctl_x86_get_xsave(vcpu, u.xsave);
+		kvm_vcpu_ioctl_x86_get_xsave(vcpu, u.xsave->region, false);
 
 		r = -EFAULT;
 		if (copy_to_user(argp, u.xsave, sizeof(struct kvm_xsave)))
@@ -4855,6 +4867,20 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		r = 0;
 		break;
 	}
+	case KVM_GET_XSAVE_EXTENSION: {
+		u.xsave_ext = kzalloc(sizeof(struct kvm_xsave_extension), GFP_KERNEL_ACCOUNT);
+		r = -ENOMEM;
+		if (!u.xsave_ext)
+			break;
+
+		kvm_vcpu_ioctl_x86_get_xsave(vcpu, u.xsave_ext->region, true);
+
+		r = -EFAULT;
+		if (copy_to_user(argp, u.xsave_ext, sizeof(struct kvm_xsave_extension)))
+			break;
+		r = 0;
+		break;
+	}
 	case KVM_SET_XSAVE: {
 		u.xsave = memdup_user(argp, sizeof(*u.xsave));
 		if (IS_ERR(u.xsave)) {
@@ -4862,7 +4888,17 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 			goto out_nofree;
 		}
 
-		r = kvm_vcpu_ioctl_x86_set_xsave(vcpu, u.xsave);
+		r = kvm_vcpu_ioctl_x86_set_xsave(vcpu, u.xsave->region);
+		break;
+	}
+	case KVM_SET_XSAVE_EXTENSION: {
+		u.xsave_ext = memdup_user(argp, sizeof(*u.xsave_ext));
+		if (IS_ERR(u.xsave_ext)) {
+			r = PTR_ERR(u.xsave_ext);
+			goto out_nofree;
+		}
+
+		r = kvm_vcpu_ioctl_x86_set_xsave(vcpu, u.xsave_ext->region);
 		break;
 	}
 	case KVM_GET_XCRS: {
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index ca41220b40b8..42a167a29350 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1053,6 +1053,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_X86_USER_SPACE_MSR 188
 #define KVM_CAP_X86_MSR_FILTER 189
 #define KVM_CAP_ENFORCE_PV_FEATURE_CPUID 190
+#define KVM_CAP_X86_XSAVE_EXTENSION 191
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -1462,6 +1463,13 @@ struct kvm_s390_ucas_mapping {
 /* Available with KVM_CAP_XSAVE */
 #define KVM_GET_XSAVE		  _IOR(KVMIO,  0xa4, struct kvm_xsave)
 #define KVM_SET_XSAVE		  _IOW(KVMIO,  0xa5, struct kvm_xsave)
+/*
+ * Available with KVM_CAP_XSAVE_EXTENSION
+ * 0xa4/0xa5 are ok for the new ioctls since structure size is different.
+ */
+#define KVM_GET_XSAVE_EXTENSION   _IOW(KVMIO,  0xa4, struct kvm_xsave_extension)
+#define KVM_SET_XSAVE_EXTENSION   _IOW(KVMIO,  0xa5, struct kvm_xsave_extension)
+
 /* Available with KVM_CAP_XCRS */
 #define KVM_GET_XCRS		  _IOR(KVMIO,  0xa6, struct kvm_xcrs)
 #define KVM_SET_XCRS		  _IOW(KVMIO,  0xa7, struct kvm_xcrs)
-- 
2.18.4


  parent reply	other threads:[~2021-02-07  6:59 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-07 15:42 [PATCH RFC 0/7] Introduce support for guest AMX feature Jing Liu
2021-02-07 15:42 ` [PATCH RFC 1/7] kvm: x86: Expose XFD CPUID to guest Jing Liu
2021-05-24 21:34   ` Sean Christopherson
2021-06-07  3:27     ` Liu, Jing2
2021-02-07 15:42 ` [PATCH RFC 2/7] kvm: x86: Introduce XFD MSRs as passthrough " Jing Liu
2021-05-24 21:43   ` Sean Christopherson
2021-05-24 21:57     ` Jim Mattson
2021-06-02  3:12     ` Liu, Jing2
2021-06-23 17:50     ` Dave Hansen
2021-06-28  2:00       ` Liu, Jing2
2021-06-29 17:58         ` Dave Hansen
2021-07-06  7:33           ` Liu, Jing2
2021-02-07 15:42 ` [PATCH RFC 3/7] kvm: x86: XSAVE state and XFD MSRs context switch Jing Liu
2021-02-07 11:49   ` Borislav Petkov
2021-02-08  3:35     ` Liu, Jing2
2021-02-08 10:25   ` Paolo Bonzini
2021-02-08 17:31     ` Sean Christopherson
2021-02-08 17:45       ` Paolo Bonzini
2021-02-08 18:04         ` Sean Christopherson
2021-02-08 18:12           ` Paolo Bonzini
2021-02-08 18:55             ` Konrad Rzeszutek Wilk
2021-02-22  8:51               ` Liu, Jing2
2021-02-22  8:36             ` Liu, Jing2
2021-02-07 15:42 ` Jing Liu [this message]
2021-05-24 21:50   ` [PATCH RFC 4/7] kvm: x86: Add new ioctls for XSAVE extension Sean Christopherson
2021-05-26  6:09     ` Liu, Jing2
2021-05-26 14:43       ` Sean Christopherson
2021-06-01 10:24         ` Liu, Jing2
2021-06-07  5:23           ` Liu, Jing2
2021-05-24 22:06   ` Jim Mattson
2021-05-26  6:11     ` Liu, Jing2
2021-02-07 15:42 ` [PATCH RFC 5/7] kvm: x86: Revise CPUID.D.1.EBX for alignment rule Jing Liu
2021-05-24 21:28   ` Sean Christopherson
2021-06-03  4:45     ` Liu, Jing2
2021-02-07 15:42 ` [PATCH RFC 6/7] kvm: x86: Add AMX_TILE, AMX_INT8 and AMX_BF16 support Jing Liu
2021-02-07 15:42 ` [PATCH RFC 7/7] kvm: x86: AMX XCR0 support for guest Jing Liu
2021-05-24 21:53   ` Sean Christopherson
2021-05-26  7:54     ` Liu, Jing2
2021-05-26 14:54       ` Sean Christopherson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210207154256.52850-5-jing2.liu@linux.intel.com \
    --to=jing2.liu@linux.intel.com \
    --cc=jing2.liu@intel.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=seanjc@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).